The present invention relates to the security systems and more particularly to the structure of a key defining a code for operating a coded security system. More particularly, the invention is directed toward the structure of a key having a grip portion upon which there are held a plurality of information carrier members which may be rotated relative to each other in a predetermined angular pattern to establish the code of the security system.
Keys of this type are known from German Pat. No. 2138991. The secret code of the key is determined by the relative angular positioning of a plurality of information carrier members which comprise magnetic devices. The key usually will operate a mechanical lock having tumblers which are unlocked by switch magnets located in the lock housing when a magnetic field with a predetermined direction is applied to the switch magnet by means of the key. The known key has two magnets which are arranged in a plane adjacent each other and which are held on locking discs. The magnets may be rotated about an axis which extends perpendicularly to the direction of magnet polarization. By rotating the locking discs, the angular position of the direction of polarization relative to each of the carrier members may be changed and the key may be coded to a desired code.
A disadvantage of the known key structure is the disproportionately increasing space requirement of the key when a higher number of coding variations must be provided. Moreover, adjustment of the locking discs may be relatively easily changed which is undesirable from the point of view of utilization of the key.
The invention is directed toward providing a relatively small key having a relatively higher number of coding variations wherein the secret code of the key may be changed in a simple manner while still providing protection against unintentional changes in the code.